overview

There are user controls and custom controls:

• User controls have hardcoded UI’s in their XAML files
• Custom controls have UIs defined in a ControlTemplate.
  • Set the Template property to change the UI of a custom control.
  • This allows for changing the UI even if you don’t own the code for the control.
• All WinUI controls (Button, TextBox, CheckBox, etc) are implemented as custom controls.

define the look of a custom control

Starting with a normal grey button…

Now:

1. Assign a ControlTemplate with target type Button to the Button’s Template property.
2. Create the UI for the Button (using any UI element like Shape, Panel, etc) inside the ControlTemplate tag.

You now have an orange circular button:

Setting the Button’s Background property to Blue has no effect because it is overriden by the ControlTemplate:

Use the TemplateBinding static markup extension to reference a property:

A ControlTemplate can also be defined in a Style: